The lymphatic vascular system is composed of a dense network of thin-walled capillaries that drain protein-rich lymph from the extracellular space. Its major roles include the maintenance of tissue fluid homeostasis and mediation of the afferent immune response (Oliver et al. (2002) Genes Dev. 16:773-83; Witte et al. (2001) Microsc. Res. Tech. 55:122-45). One known function of lymphatic vessels is the drainage of tissue fluid from normal and inflamed tissues (Kunstfeld et al. (2004) Blood 104:1048-57).